Stamp printing process

There are several ways to print stamps:

1. Mitigation

Letterpress printing is the oldest in the history of printing, and modern books and newspapers mostly use letterpress printing. The principle of letterpress printing is that there are convex parts and concave parts on the printing plate, the convex parts of the seal pattern have ink, and the concave parts have no ink. When printing, the paper is placed on the printing plate, and the ink of the raised part is printed on the paper through a certain pressure, which is the same as the principle of hot stamping.

Many early stamps in the world were printed in relief. The 1 set of stamps issued in China-"Dragon" stamps and some stamps issued in the liberated areas are also embossed. The relief stamps issued by China People's Post include the second group of ordinary stamps.

Relief printing has the advantage of simple process, but poor artistic effect. Nowadays, there are not many stamps printed by letterpress. But when printing words on printed stamps, most of them still use letterpress.

2. Gravure printing

Gravure printing also has a long history. 1 World1stamp issued in 840-British black penny stamp is printed in intaglio. Due to the complexity of intaglio plate making, it is not easy to forge, and the effect is good, banknotes, bonds, stocks, stamps and so on all over the world are mostly printed in intaglio. The printing principle of intaglio is just the opposite of relief. There are also convex parts and concave parts on the printing plate. After the seal pattern is coated with ink on the printing plate in the concave part, the ink in the convex part is scraped off with a scraper, and the ink is only left in the concave part. Put the paper on the page and press it, and the recessed ink will be printed on the paper.

Gravure is divided into engraved intaglio, photographic intaglio and multicolor engraved plate.

Engraving intaglio is generally called engraving, and its plate-making process is complicated. First of all, specially trained sculptors must accurately carve pictures and words with the same size as stamps on steel plates. Because of the small carving area, only with the help of a magnifying glass can we see the changes of points and lines clearly. After the carving process is completed, it is called the original outline version, which can be printed after proofing. The whole carving process of carving board is manual operation, which is time-consuming and expensive. The advantage is that the original is hand-carved, which is not easy to forge and has the artistic characteristics of printmaking.

Gravure printing, also called shadow printing plate, is an intaglio made by photography. It has the advantages of fine mesh and deep plate grain. The basic method is to take the photographic negative as a template and screen it, so that after the photosensitive film is exposed, the image is transferred to the printing plate cylinder and etched to form a printing plate. Gravure stamps are called shadow plates because of their clear layering, vivid images and printing effect close to photography.

Multicolor engraving is a new technology in stamp printing. When printing multi-color engraved seals by this method, it can be completed at one time without overprinting for many times. In this printing method, the engraving still adopts the conventional plate-making process, and several ink roller devices are installed on the printing machine. When the machine is started, each ink roller delivers one color of ink to different parts of the printed pattern, so that the printing plate can get several colors at the same time, and it will show multi-color effect when printed on white paper.

Mixed overprinter of block printing and shadow printing. This kind of overprint can give full play to the advantages of the two printing methods, make the colors rich and the lines clear, and obtain a better printing effect. This printing method is to print a shadow first, write a version, and perform well to harmonize levels; Reprint the block prints, mainly outlines and figures, to make the picture richer, more delicate and more complete.

3. Offset printing

Offset printing, also known as offset printing, is the most common one in lithography. It is different from relief printing and gravure printing. The printing plate is flat and has no convex and concave parts. Instead, using the principle of oil-water incompatibility, the ink is only adsorbed on the layout of the seal pattern part, while the blank part is hydrophilic and cannot be inked. The pattern of the printing plate is first printed on the rubber-coated roller, and then transferred to paper. Offset printing is characterized by simple process, large printing volume, short cycle and low cost, but it is easy to be imitated, which is its shortcoming.

How to print stamps? On the one hand, when designing, we should consider which version can achieve the expected artistic effect; On the other hand, we should also consider the printing technical conditions at that time.